A general compilation of the results fronn the San Francisco Bay and 

 Gulf of Mexico field tests and the FY-68 and FY-71 laboratory tests is given 

 in Table 2. Some of the terms require further definition as follows: 



B — The smallest lateral object dimension (width). For 



spheres and cylinders, this is taken as the object width 

 at the soil— water interface. 



A — Object cross-sectional area. For spheres and cylinders, 

 this is taken at the soil— water interface. 



W3 — Buoyant weight of soil displaced by object (equal to 

 the buoyant unit weight of soil, 75, times the volume 

 of the portion of object embedded in soil, Vj). 



W^, — Buoyant weight of object. 



F^, — Breakout force carried by soil (equal to F^^J - Wj^ +W5). 



Fq — Downward force carried by soil during waiting period 

 prior to breakout loading (equal to W^ - W^ - Fg^^). 



D — Embedment depth (assumed equal to V^/A for spheres 

 and cylinders). 



Sy — Vane shear strength of soil. 



The rationale behind the use of Fj^ and F^ is discussed in the 

 ANALYSIS section. The value of soil vane shear strength is not given for 

 the field tests because, as will be seen later, the quantity F^ is a better mea- 

 sure of the in-situ undrained shear strength. Measurements of vane shear 

 strength at both sites were made, however, and these are listed in References •'" 

 6 and 7. The vane shear strength for the FY-68 laboratory tests is derived 

 from data presented in Reference 7. The vane shear strength is taken as 3.5 

 psf for embedment depths, D, less than 2 inches and equal to 5 psf for greater 

 embedment depths. For the FY-71 tests, vane shear strength was measured 

 with a hand vane at eight points in the test tank after each test. The results 

 were averaged according to the procedure outlined in Appendix A to yield 

 one characteristic vane strength for each test. 



ANALYSIS 



General 



Breakout is a very complex soil mechanics problem. Two of the 

 features which make it so are: 



